nile13

My A/C has been pretty warm all summer and, I believe, was the same last year when I bought the car. So I'm trying to sort it out.

1. Have not check the pressure yet. Need to find the gauge to do so and will.

2. Had jumped the front resistor to run on constant high to take it out of equation.

3. Started the car today, turn A/C on max and looked around the compressor. The compressor itself got hot within about a minute and a half. I did not expect it to get that hot that fast. Is this normal? The two big lines going to the high and low side... the rearmost one (high side) got hot, the low side stayed just below room temperature.

My question is, before I test the pressure, is it normal for compressor to get hot that fast? Should high side be hot and low side cool/cold? Any other ideas here?

techman1

I will check how quickly to give you a comparison. About to leave work, will post results when I get home.

nile13

That would be great, thanks!

techman1

Here is some info to maybe help:
Car from at rest 2+hours. Cranked up, AC Max button pushed in. Opened engine cover, had hand on high/low pipes within 10 seconds. Shortly therafter one got hot, quick, and the other got pretty cold quickly. All within 5 seconds on getting my hands on them. Total time of about 15 seconds!
A guess:
If yours is getting hot fast, My thought is the compressor is doing its work, which generates heat as a byproduct. If the cold side is not getting cold as quick, coolant is low?

Pete Lech

I am only getting 50 degrees out of the center vent, maybe a little lower at high speed on the freeway. Get one of those inexpensive little refrigeration thermometers - dial on the end of a skinny probe and stick it in the vent.

50 degrees ain't great, but it works with enough air flow in the car.

nile13

Techman, thanks!

I agree, I think my coolant is low. So the next step is to check the coolant pressure and add some and see if it leaks. Unless there are some other suggestions that's what I'll do.

SuperUser

I bet you can borrow the tools from your local Autozone.

nile13

Hmm, interesting idea. I was there just a couple hours ago looking at pathetic stuff they have (no good A/C gauges at all). Should have asked them about what they have to borrow. Will do tomorrow.

2Many Cars

I would agree the charge is probably low. It's best not to run the compressor too much if that's the case.

It used to be that the receiver/dryer had a sight glass on the top. Back in the R12 days you'd watch it to see if you could see bubbles going by when the compressor was running. If you saw lots of bubbles the coolant charge was low. I know that doesn't work for older systems with R-134 conversions but I believe our cars came with an updated system and 134 as a stock fill but I'm not sure if the old rules apply to the newer systems. Maybe someone here knows if bubbles in the sight glass is still a tipoff on the newer systems.

levtron

Had a weak A/C this summer... I did not bother checking the levels. Just went to Autozone and bought the larger R-bottle, then too Andrey's house and he had the better a/c charge cable with single gauge. It was low. The system ended up taking almost the entire can. All working fine now. I added the rest to my other car that I know has a leak, so I got 2:1 out of one bottle.

nile13

Lev, that's probably what I'll end up doing as well.

Saw a bunch of different R134a cans at AZ this morning. Some with oil, some without, etc. Do you recall which one you got?

Pete Lech

Click & Clack had a discussion on this last Saturday. I believe the consensus was if you think your system is semi-toast, get the one with stopleak and oil. Otherwise just the plain R134A is safer. Wallymart sells the can with a reusable gauge for a few $$ more than without.

Body Roll

I'll put this out there- after several years of putting up with mediocre AC in the 993, I finally took the car to a real mechanic. For an hour of labor and about $50 worth of refrigerant, they evacuated and charged the system properly as well as checked codes in the CCU.

This was completely worth it. I had spent many hours fooling around trying to fix the system myself but could not get it right. (I'm pretty sure it was overcharged initially- it would short cycle on low fan speeds and the pressures were high.)

Now the AC works pretty well. It's not as good as my Volkswagen, but it keeps up with San Diego hot weather.

loubeer

A few comments. I agree with PSAGAZIO - worth going to see an AC pro - the good ones have amazing diagnostic tools to determine problems, leaks, etc. Also, not wise to run the compressor if refrigerant low/leaking. Hate to bring this up, but if refrigerant low, could be a problem with evaporator unit springing a leak. Our cars are getting grey whiskers - these things will happen - ask me how I know!

2Many Cars

Usually if there is a leak the system will be empty in a relatively short period of time. If you've been low all summer (which it sounds like you have) it's probably just the normal loss of refrigerant through the hoses that happens over time - in which case a simple recharge should do the trick. Also, unless you've had a leak you shouldn't need to add more oil, just the refrigerant.